docs: def add_notes(self, notes):
          """Feed notes to self.add_note.
  
          The notes can either be an other NoteContainer, a list of Note
          objects or strings or a list of lists formatted like this:
          >>> notes = [['C', 5], ['E', 5], ['G', 6]]
  
          or even:
          >>> notes = [['C', 5, {'volume': 20}], ['E', 6, {'volume': 20}]]
          """
          if hasattr(notes, 'notes'):
              for x in notes.notes:
                  self.add_note(x)
              return self.notes
          elif hasattr(notes, 'name'):
              self.add_note(notes)
              return self.notes
          elif type(notes) == str:
              self.add_note(notes)
              return self.notes
          for x in notes:
              if type(x) == list and len(x) != 1:
                  if len(x) == 2:
                      self.add_note(x[0], x[1])
                  else:
                      self.add_note(x[0], x[1], x[2])
              else:
                  self.add_note(x)
          return self.notes